Light-Emitting Diodes (LED) can have advantages such as: power-efficient, orientation-controllable, color-display-stable, high reliability, long service life, small sizes, and environmental safety, etc. As such, LEDs are particularly suitable for LED colorful light-emitting apparatus, such as colorful lanterns, decoration lights, etc. A colorful light-emitting apparatus can have multiple LEDs wired in either series or parallel. There is a strong demand for LED lights for holiday decorations such as Christmas, and in applications such as celebrations, entertainment, and night scenery.
LED lights can be in a steady mode, or a flicker mode. LEDs in a steady mode are easier to manufacture, but with monotonous decoration effects. Those methods to manufacture LED lighting strings in flicker mode include: LED flashbulbs are installed among steady mode LEDs with fixed mode and without any change modes controlled by signals; LED lights are divided into several groups controlled by the controller for each group. To make the LED lighting strings work like water flowing, it must be adapted for over 3-channels structure, and the more channels the better the effect of lighting.
The mode to divide an LED lighting string into several LED groups needs to connect those LEDs which lighting at same time in series, and then to connect each group in parallel. The more channels of the LED colorful light is used with more complex structure, more electric wire, more manufacturing difficulty, and higher cost, also with larger size, various parts, and high cost of products.
Chinese invention patent CN1423515 discloses a variable colorful light band for decorating, which comprises a controller to provide trigger voltage and several variable color switch circuits. Each variable color switch circuit comprises two bidirectional controllable silicon which connecting with rectifier diode in series and then connecting with the third bidirectional controllable silicon in parallel. The controlling ports of three bidirectional controllable silicon are connected with the controller. One port of the parallel circuit connects the power and another port connects a plurality of variable colorful LED bulbs. The solution adopts a simple method by controllable silicon circuits to change three colors. But when need to controlling more various colorful mode, the circuit is very complex.
Chinese utility model patent CN203206544U discloses a double-wire LED lighting string with two sets of LED lamps flashing circularly. The double-wire LED lighting string comprises wires and a plurality of LED lamps. All LED lamps are connected in parallel by two wires in the order of that the anode of an LED lamp is connect with the cathode of the next LED lamp, and the cathode of the LED lamp is connected with the anode of the next LED lamp circularly. One wire connected in parallel connect to the first output of a control unit electrically, while the other wire connected in parallel connect to the second output of the control unit. The positive and negative polarities of the first output and the second output of the control unit are interchanged intermittently. It just needs two output wires of the control system, and needs two wires to realize two loop channels of the LED lighting string. In this way, lots of wires are saved, but only achieving two kind of color.
Chinese invention patent CN103528014A discloses an LED Christmas lantern controlled by an IC chip. The LED Christmas lantern comprises a transformer, a controller, an always-on LED lighting channel and a controllable LED lighting channel. The point by point control of the controllable LED lighting channel can be got by the IC control module without any special LED lamp, thus a rich variation of light effects of the controllable LED lighting string is achieved. The scheme requires two separate channel, which are always-on LED lighting channel and controllable LED lighting channel. The IC chip of controllable LED lighting channel needs to connect individually.
Chinese invention patent CN101598277 discloses an LED lighting string using only two wires, which the input port of a coding controller is connected to a power, the output port of the coding controller is connected with two wires, a plurality of LEDs are connected in parallel by the wires to form a multi-channel LED lighting string. Each chip identified by a same number within the same lighting channel is built in the LEDs, while the identified numbers are different in the different lighting channel. The coding controller is connected to transmission circuits via the output port of carrier circuits. The output port of pulse receiving circuit is connected to decoding circuit. The LEDs in different channels with different identified chips brings two disadvantages, one that the coding identifying chip requires read-only memory (ROM) to store code with the higher complexity of coding identifying chip, the other is that the products need to assemble by different identifying codes during the manufacture. If the identified chips are assembly at wrong position, the effect of decoration can't achieve to the expected. This consults in the complexity to assemble final productions.